Monte-Carlo simulations to measure the temporal and optical performance of a laserball calibration device. Written by Sammy Valder and Martti Nirkko, University of Sussex, (2022).
The simulations have been tested and are working using:
gcc 5.4.0
root 5.34
First clone the repository
git clone git@github.com:svalder/laserball-MC.git
Update the parameters of the simulation using the configuration file include/config.C
Compile the code using g++ -g -o diffuser.exe diffuser.C `root-config --cflags --libs` - this should be done each time a change is made to the config file
Run the simulation using the executable created when compiling ./diffuser.exe
The configuration file can be found at include/config.C. The default parameters in this repository reflect the real-life laserball calibration device developed at the University of Sussex for the scintillator phase of the SNO+ experiment. The parameters are split into sections:
Independent variable - this selects the variable of interest to change during simulation: 0 = the light injection point which can be displaced verticallay, 1 = glass microsphere concentration inside the scattering medium. These are the two main variables known to effect the optical and temporal performance.
Global Constants - Simulation constants: verbosity defining the level of detail printed whilst running, the number of photons to be simulated, and te number of bins defining the resolution of plots created.
Laser - Constants defining the characteristics of the light injection including intensity, numerical apeture, and wavelength.
Diffuser Ball - Constants realted to the physical properties of the diffusing flask.
Glass bubbles - Constants defining the characteristics of the glass microspheres.
Quartz rod - Defining the length, diameter, and light injection offset (when kept constant) of thw quartz rod injector.
Other - Miscellaneous constants.
The output from the simulation takes the form of a ROOT file with the name diffuser.root.
The contents of the root file can be examined using standard ROOT techniques, e.g. root -l, new TBrowser(), etc...
The root file will contain a number of histograms for each of the different values defined in the independent variable array var[]. These include:
hesc - A distribution of the time it takes for the photons to exit the diffuser flask once injected.
hphi - A distribution of the number of photons exiting the diffuser as a function of azimuthal angle.
hcth - A distribution of the number of photons exiting the diffuser as a function of polar angle.
hang - A 2D plot of the angular distribution of photons exiting the diffuser, combining polar and azimuthal information.
htop - A 2D plot of the temporal distribution of photons exiting the diffuser as a function of polar angle.
htag - A 3D plot of the temporal distribution of photons exiting the diffuser, combining the polar and azimuthal information.
The standard units used are: time [ns], cos(angle) [pi], light injection displacement [mm].
When publishing material that contains simulated data using this work, please ensure the code is referenced at all times.
You can reference this work through the SNO+ scintillator laserball paper: S. Valder et al 2024 JINST 19 T01005 DOI: 10.1088/1748-0221/19/01/T01005